A tactile display has been researched as one of a human machine interface of a computer. Many of conventional tactile displays have a plurality of pins arranged in a grid and is configured capable of adjusting the height of each pin (Patent document 1, for example). A person touches a relief composed of tips of a plurality of pins. The tactile display can provide the person with various types of information as tactile perception by changing a shape of the relief surface. In order to realize various surface shapes, it has been believed as preferable that the tactile display has more pins densely arranged.
The tactile display is not limited to a display that applies a tactile stimulus on a human by changing the surface shape of the relief. Patent document 2, for example, refers to a tactile display that adopts vibrational stimulation or electrical stimulation. Patent document 2 describes that such a tactile display can convey to a human a difference in surface roughness by applying the vibrational stimulation or electrical stimulation on a human fingertip.
A research which adapts a tactile display to a CAD system is known (Non patent document 1, for example). The CAD system adopts a tactile display having a structure in which a paddle is supported by an arm and the paddle is provided for shaving a surface of a workpiece. A movement of the paddle is input to a computer by way of a movement of the arm. Also, the CAD system displays, on a monitor, surface shape data of a workpiece stored in the computer as a virtual object model (a CAD model). The computer of the CAD system reproduces the movement of the paddle in a virtual spare in the computer, and calculates interference between the virtual object model and the paddle. The CAD system can convey to an operator a reaction force, using the arm, which the paddle receives by contacting with the virtual object model in the virtual space in the computer. The operator moves the paddle, as though he/she shaved the virtual object model while watching the monitor, then the CAD system modifies the virtual object model, i.e., the surface shape data in response to the movement of the paddle.